net: mqtt: Maintain count of PINGREQ awaiting response
Maintain a simple count of how many PINGREQ have been sent for the
current connection that have not had a corresponding PINGRESP. Nothing
is done with this information internal to the MQTT driver, but it is
exposed to the application layer to monitor as desired.
Signed-off-by: Justin Brzozoski <justin.brzozoski@signal-fire.com>
diff --git a/include/net/mqtt.h b/include/net/mqtt.h
index a619baf..cac22cf 100644
--- a/include/net/mqtt.h
+++ b/include/net/mqtt.h
@@ -499,6 +499,9 @@
/** MQTT protocol version. */
u8_t protocol_version;
+ /** Unanswered PINGREQ count on this connection. */
+ s8_t unacked_ping;
+
/** Will retain flag, 1 if will message shall be retained persistently.
*/
u8_t will_retain : 1;
diff --git a/subsys/net/lib/mqtt/mqtt.c b/subsys/net/lib/mqtt/mqtt.c
index 55cd5db..2ca7cd3 100644
--- a/subsys/net/lib/mqtt/mqtt.c
+++ b/subsys/net/lib/mqtt/mqtt.c
@@ -111,6 +111,9 @@
client->internal.last_activity = mqtt_sys_tick_in_ms_get();
+ /* Reset the unanswered ping count for a new connection */
+ client->unacked_ping = 0;
+
MQTT_TRC("Connect completed");
return 0;
@@ -548,6 +551,12 @@
err_code = client_write(client, packet.cur, packet.end - packet.cur);
+ if (client->unacked_ping >= INT8_MAX) {
+ MQTT_TRC("PING count overflow!");
+ } else {
+ client->unacked_ping++;
+ }
+
error:
mqtt_mutex_unlock(client);
diff --git a/subsys/net/lib/mqtt/mqtt_rx.c b/subsys/net/lib/mqtt/mqtt_rx.c
index 6f8b29a..84801ce 100644
--- a/subsys/net/lib/mqtt/mqtt_rx.c
+++ b/subsys/net/lib/mqtt/mqtt_rx.c
@@ -120,6 +120,13 @@
case MQTT_PKT_TYPE_PINGRSP:
MQTT_TRC("[CID %p]: Received MQTT_PKT_TYPE_PINGRSP!", client);
+ if (client->unacked_ping <= 0) {
+ MQTT_TRC("Unexpected PINGRSP");
+ client->unacked_ping = 0;
+ } else {
+ client->unacked_ping--;
+ }
+
/* No notification of Ping response to application. */
notify_event = false;
break;
